1. Field of the Invention
The present invention relates to an optical disk having a wobble pre-groove, such as a rewritable CD disk and a rewritable photomagnetic disk, and more particularly to a double density recording/reproducing system suitable for a phase change CD disk recording/reproducing apparatus.
2. Related Background Art
An optical disk is known which is used with computers and records data on a groove and a land between adjacent land portions. The groove is straight and address information is recorded as pits on the groove. Addresses are radially formed on sectors, and address information pits are recorded at the top of the sector of each track.
Such a conventional optical disk records data on both the groove and land so that a record capacity is doubled as compared to a disk which records data only on the groove. However, there is a problem that a sufficiently high record density is difficult because the disk is rotated at a constant angular velocity (CAV) and the groove has address information pits. It is also impossible to read address information from the disk for data recording/reproducing to and from the land.